The purposes of this project are to: 1) evaluate the effects of : A)lipid- lowering drugs (lovastatin) in an intense versus moderate lowering of LDL cholesterol levels, B) low dose of warfarin, and C) the two in combination on past CABG saphenous vein graft patency and 2) to evaluate the effects of these interventions on progression of coronary atherosclerosis in native vessels and internal mammary grafts, ventricular function, morbidity, and quality of life.